CVE-2021-1586: high-severity vulnerability in Cisco NX-OS System Software in ACI Mode
Cisco Nexus 9000 Series Fabric Switches ACI Mode Multi-Pod and Multi-Site TCP Denial of Service Vulnerability
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.6epss 2.5%
A vulnerability in the Multi-Pod or Multi-Site network configurations for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to unexpectedly restart the device, resulting in a denial of service (DoS) condition. This vulnerability exists because TCP traffic sent to a specific port on an affected device is not properly sanitized. An attacker could exploit this vulnerability by sending crafted TCP data to a specific port that is listening on a public-facing IP address for the Multi-Pod or Multi-Site configuration. A successful exploit could allow the attacker to cause the device to restart unexpectedly, resulting in a DoS condition.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Affected products
Cisco · Cisco NX-OS System Software in ACI ModeRelated CVEs — Cisco NX-OS System Software in ACI Mode
In the same product, most dangerous first.
CVE-2026-76455CRITICALCisco NX-OS Software Security Hardening Release: October 2026 - Improper Access Control VulnerabilitiesEPSS 3.6%CVE-2025-20292MEDIUMCisco NXOS Software Command Injection VulnerabilityEPSS 3.2%CVE-2021-1230HIGHCisco Nexus 9000 Series Fabric Switches ACI Mode BGP Route Installation Denial of Service VulnerabilityEPSS 1.5%CVE-2021-1523HIGHCisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service VulnerabilityEPSS 1.3%CVE-2021-1584MEDIUMCisco Nexus 9000 Series Fabric Switches ACI Mode Privilege Escalation VulnerabilityEPSS 0.4%CVE-2024-20289MEDIUMCisco NX-OS Software Command Injection VulnerabilityEPSS 0.4%